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Split out the Disk II controller state

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This change factors the emulated hardware state into a separate
structure in the Disk II controller.  The idea is that this hardware
state will be able to be shared with the WOZ and nibble disk code
instead of sharing _all_ of the controller state (like callbacks and
so forth).
This commit is contained in:
Ian Flanigan 2022-08-30 09:11:02 +02:00
parent e9772de847
commit c0ba9cca55
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GPG Key ID: 035F657DAE4AE7EC
2 changed files with 124 additions and 102 deletions
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218
js/cards/disk2.ts
View File

@ -167,6 +167,35 @@ const PHASE_DELTA = [
[1, -2, -1, 0]
] as const;
/**
* State of the controller.
*/
interface ControllerState {
/** Sectors supported by the controller. */
sectors: SupportedSectors;
/** Is the active drive powered on? */
on: boolean;
/** The active drive. */
drive: DriveNumber;
/** The 8-cycle LSS clock. */
clock: LssClockCycle;
/** Current state of the Logic State Sequencer. */
state: nibble;
/** Q6 (Shift/Load) */
q6: boolean;
/** Q7 (Read/Write) */
q7: boolean;
/** Last data from the disk drive. */
latch: byte;
/** Last data written by the CPU to card softswitch 0x8D. */
bus: byte;
}
/** Callbacks triggered by events of the drive or controller. */
export interface Callbacks {
/** Called when a drive turns on or off. */
@ -180,8 +209,8 @@ export interface Callbacks {
/** Called when a disk is inserted or removed from the drive. */
label: (drive: DriveNumber, name?: string, side?: string) => void;
}
/** Common information for Nibble and WOZ disks. */
/** Common information for Nibble and WOZ disks. */
interface BaseDrive {
/** Current disk format. */
format: NibbleFormat;
@ -244,13 +273,12 @@ interface DriveState {
metadata: DiskMetadata;
}
/** State of the controller for saving/restoring. */
// TODO(flan): It's unclear whether reusing ControllerState here is a good idea.
interface State {
drives: DriveState[];
skip: number;
latch: number;
q7: boolean;
on: boolean;
drive: DriveNumber;
controllerState: ControllerState;
}
function getDriveState(drive: Drive): DriveState {
@ -354,38 +382,24 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
}
};
private state: ControllerState;
/**
* When `1`, the next nibble will be available for read; when `0`,
* the card is pretending to wait for data to be shifted in by the
* sequencer.
*/
private skip = 0;
/** Last data written by the CPU to card softswitch 0x8D. */
private bus = 0;
/** Drive data register. */
private latch = 0;
/** Drive off timeout id or null. */
private offTimeout: number | null = null;
/** Q6 (Shift/Load): Used by WOZ disks. */
private q6 = 0;
/** Q7 (Read/Write): Used by WOZ disks. */
private q7: boolean = false;
/** Whether the selected drive is on. */
private on = false;
/** Current drive number (1, 2). */
private drive: DriveNumber = 1;
/** Current drive object. */
private cur = this.drives[this.drive];
private cur: Drive;
/** Nibbles read this on cycle */
private nibbleCount = 0;
/** The 8-cycle LSS clock. */
private clock: LssClockCycle = 0;
/** Current CPU cycle count. */
private lastCycles = 0;
/** Current state of the Logic State Sequencer. */
private state: nibble = 0;
/**
* Number of zeros read in a row. The Disk ][ can only read two zeros in a
* row reliably; above that and the drive starts reporting garbage. See
@ -400,12 +414,24 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
this.debug('Disk ][');
this.lastCycles = this.io.cycles();
// From the example in UtA2e, p. 9-29, col. 1, para. 1., this is
// essentially the start of the sequencer loop and produces
// correctly synced nibbles immediately. Starting at state 0
// would introduce a spurrious 1 in the latch at the beginning,
// which requires reading several more sync bytes to sync up.
this.state = 2;
this.state = {
sectors,
bus: 0,
latch: 0,
drive: 1,
on: false,
q6: false,
q7: false,
clock: 0,
// From the example in UtA2e, p. 9-29, col. 1, para. 1., this is
// essentially the start of the sequencer loop and produces
// correctly synced nibbles immediately. Starting at state 0
// would introduce a spurrious 1 in the latch at the beginning,
// which requires reading several more sync bytes to sync up.
state: 2,
};
this.cur = this.drives[this.state.drive];
this.initWorker();
}
@ -465,10 +491,12 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
}
const track =
this.cur.rawTracks[this.cur.trackMap[this.cur.track]] || [0];
const state = this.state;
while (workCycles-- > 0) {
let pulse: number = 0;
if (this.clock === 4) {
if (state.clock === 4) {
pulse = track[this.cur.head];
if (!pulse) {
// More than 2 zeros can not be read reliably.
@ -482,47 +510,47 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
let idx = 0;
idx |= pulse ? 0x00 : 0x01;
idx |= this.latch & 0x80 ? 0x02 : 0x00;
idx |= this.q6 ? 0x04 : 0x00;
idx |= this.q7 ? 0x08 : 0x00;
idx |= this.state << 4;
idx |= state.latch & 0x80 ? 0x02 : 0x00;
idx |= state.q6 ? 0x04 : 0x00;
idx |= state.q7 ? 0x08 : 0x00;
idx |= state.state << 4;
const command = SEQUENCER_ROM[this.sectors][idx];
this.debug(`clock: ${this.clock} state: ${toHex(this.state)} pulse: ${pulse} command: ${toHex(command)} q6: ${this.q6} latch: ${toHex(this.latch)}`);
this.debug(`clock: ${state.clock} state: ${toHex(state.state)} pulse: ${pulse} command: ${toHex(command)} q6: ${state.q6} latch: ${toHex(state.latch)}`);
switch (command & 0xf) {
case 0x0: // CLR
this.latch = 0;
state.latch = 0;
break;
case 0x8: // NOP
break;
case 0x9: // SL0
this.latch = (this.latch << 1) & 0xff;
state.latch = (state.latch << 1) & 0xff;
break;
case 0xA: // SR
this.latch >>= 1;
state.latch >>= 1;
if (this.cur.readOnly) {
this.latch |= 0x80;
state.latch |= 0x80;
}
break;
case 0xB: // LD
this.latch = this.bus;
this.debug('Loading', toHex(this.latch), 'from bus');
state.latch = state.bus;
this.debug('Loading', toHex(state.latch), 'from bus');
break;
case 0xD: // SL1
this.latch = ((this.latch << 1) | 0x01) & 0xff;
state.latch = ((state.latch << 1) | 0x01) & 0xff;
break;
default:
this.debug(`unknown command: ${toHex(command & 0xf)}`);
}
this.state = (command >> 4 & 0xF) as nibble;
state.state = (command >> 4 & 0xF) as nibble;
if (this.clock === 4) {
if (this.on) {
if (this.q7) {
track[this.cur.head] = this.state & 0x8 ? 0x01 : 0x00;
this.debug('Wrote', this.state & 0x8 ? 0x01 : 0x00);
if (state.clock === 4) {
if (state.on) {
if (state.q7) {
track[this.cur.head] = state.state & 0x8 ? 0x01 : 0x00;
this.debug('Wrote', state.state & 0x8 ? 0x01 : 0x00);
}
if (++this.cur.head >= track.length) {
@ -531,8 +559,8 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
}
}
if (++this.clock > 7) {
this.clock = 0;
if (++state.clock > 7) {
state.clock = 0;
}
}
}
@ -542,28 +570,29 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
if (!isNibbleDrive(this.cur)) {
return;
}
if (this.on && (this.skip || this.q7)) {
const state = this.state;
if (state.on && (this.skip || state.q7)) {
const track = this.cur.tracks[this.cur.track >> 2];
if (track && track.length) {
if (this.cur.head >= track.length) {
this.cur.head = 0;
}
if (this.q7) {
if (state.q7) {
if (!this.cur.readOnly) {
track[this.cur.head] = this.bus;
track[this.cur.head] = state.bus;
if (!this.cur.dirty) {
this.updateDirty(this.drive, true);
this.updateDirty(state.drive, true);
}
}
} else {
this.latch = track[this.cur.head];
state.latch = track[this.cur.head];
}
++this.cur.head;
}
} else {
this.latch = 0;
state.latch = 0;
}
this.skip = (++this.skip % 2);
}
@ -582,7 +611,7 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
// 5. [...] enables head positioning [...]
//
// Therefore do nothing if no drive is on.
if (!this.on) {
if (!this.state.on) {
this.debug(`ignoring phase ${phase}${on ? ' on' : ' off'}`);
return;
}
@ -614,6 +643,7 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
}
private access(off: byte, val?: byte) {
const state = this.state;
let result = 0;
const readMode = val === undefined;
@ -645,13 +675,13 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
case LOC.DRIVEOFF: // 0x08
if (!this.offTimeout) {
if (this.on) {
if (state.on) {
// TODO(flan): This is fragile because it relies on
// wall-clock time instead of emulator time.
this.offTimeout = window.setTimeout(() => {
this.debug('Drive Off');
this.on = false;
this.callbacks.driveLight(this.drive, false);
state.on = false;
this.callbacks.driveLight(state.drive, false);
this.debug('nibbles read', this.nibbleCount);
}, 1000);
}
@ -663,37 +693,37 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
window.clearTimeout(this.offTimeout);
this.offTimeout = null;
}
if (!this.on) {
if (!state.on) {
this.debug('Drive On');
this.nibbleCount = 0;
this.on = true;
state.on = true;
this.lastCycles = this.io.cycles();
this.callbacks.driveLight(this.drive, true);
this.callbacks.driveLight(state.drive, true);
}
break;
case LOC.DRIVE1: // 0x0a
this.debug('Disk 1');
this.drive = 1;
this.cur = this.drives[this.drive];
if (this.on) {
state.drive = 1;
this.cur = this.drives[state.drive];
if (state.on) {
this.callbacks.driveLight(2, false);
this.callbacks.driveLight(1, true);
}
break;
case LOC.DRIVE2: // 0x0b
this.debug('Disk 2');
this.drive = 2;
this.cur = this.drives[this.drive];
if (this.on) {
state.drive = 2;
this.cur = this.drives[state.drive];
if (state.on) {
this.callbacks.driveLight(1, false);
this.callbacks.driveLight(2, true);
}
break;
case LOC.DRIVEREAD: // 0x0c (Q6L) Shift
this.q6 = 0;
if (this.q7) {
state.q6 = false;
if (state.q7) {
this.debug('clearing _q6/SHIFT');
}
if (isNibbleDrive(this.cur)) {
@ -702,17 +732,17 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
break;
case LOC.DRIVEWRITE: // 0x0d (Q6H) LOAD
this.q6 = 1;
if (this.q7) {
state.q6 = true;
if (state.q7) {
this.debug('setting _q6/LOAD');
}
if (isNibbleDrive(this.cur)) {
if (readMode && !this.q7) {
if (readMode && !state.q7) {
if (this.cur.readOnly) {
this.latch = 0xff;
state.latch = 0xff;
this.debug('Setting readOnly');
} else {
this.latch = this.latch >> 1;
state.latch = state.latch >> 1;
this.debug('Clearing readOnly');
}
}
@ -721,11 +751,11 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
case LOC.DRIVEREADMODE: // 0x0e (Q7L)
this.debug('Read Mode');
this.q7 = false;
state.q7 = false;
break;
case LOC.DRIVEWRITEMODE: // 0x0f (Q7H)
this.debug('Write Mode');
this.q7 = true;
state.q7 = true;
break;
default:
@ -739,7 +769,7 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
// used to read the data register onto the CPU bus, although some
// also cause conflicts with the disk controller commands.
if ((off & 0x01) === 0) {
result = this.latch;
result = state.latch;
if (result & 0x80) {
this.nibbleCount++;
}
@ -749,7 +779,7 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
} else {
// It's not explicitly stated, but writes to any address set the
// data register.
this.bus = val;
state.bus = val;
}
return result;
@ -775,12 +805,13 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
}
reset() {
if (this.on) {
this.callbacks.driveLight(this.drive, false);
this.q7 = false;
this.on = false;
this.drive = 1;
this.cur = this.drives[this.drive];
const state = this.state;
if (state.on) {
this.callbacks.driveLight(state.drive, false);
state.q7 = false;
state.on = false;
state.drive = 1;
this.cur = this.drives[state.drive];
}
}
@ -789,16 +820,10 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
}
getState(): State {
// TODO(flan): This does not accurately save state. It's missing
// all of the state for WOZ disks and the current status of the
// bus.
const result = {
drives: [] as DriveState[],
skip: this.skip,
latch: this.latch,
q7: this.q7,
on: this.on,
drive: this.drive
controllerState: { ...this.state },
};
result.drives[1] = getDriveState(this.drives[1]);
result.drives[2] = getDriveState(this.drives[2]);
@ -808,19 +833,16 @@ export default class DiskII implements Card<State>, MassStorage<NibbleFormat> {
setState(state: State) {
this.skip = state.skip;
this.latch = state.latch;
this.q7 = state.q7;
this.on = state.on;
this.drive = state.drive;
this.state = { ...state.controllerState };
for (const d of DRIVE_NUMBERS) {
this.drives[d] = setDriveState(state.drives[d]);
const { name, side } = state.drives[d].metadata;
const { dirty } = state.drives[d];
this.callbacks.label(d, name, side);
this.callbacks.driveLight(d, this.on);
this.callbacks.driveLight(d, this.state.on);
this.callbacks.dirty(d, dirty);
}
this.cur = this.drives[this.drive];
this.cur = this.drives[this.state.drive];
}
getMetadata(driveNo: DriveNumber) {

8
test/js/cards/disk2.spec.ts
View File

@ -66,11 +66,11 @@ describe('DiskII', () => {
const state = diskII.getState();
// These are just arbitrary changes, not an exhaustive list of fields.
state.drive = 2;
state.skip = 1;
state.latch = 0x42;
state.on = true;
state.q7 = true;
state.controllerState.drive = 2;
state.controllerState.latch = 0x42;
state.controllerState.on = true;
state.controllerState.q7 = true;
state.drives[2].tracks[14][12] = 0x80;
state.drives[2].head = 1000;
state.drives[2].phase = 3;